1. Field of the Invention
The present invention relates to an image forming apparatus.
2. Description of the Related Art
In Japanese Patent Application Publication No. 2007-225969, Ito describes an electrophotographic color printer. This printer includes image forming units for four colors of black, yellow, magenta, and cyan. Each of the image forming units includes a photosensitive drum, a charging unit that charges the surface of the photosensitive drum, an exposure unit that illuminates the charged surface to form an electrostatic latent image, a developing unit that develops the electrostatic latent image with toner to form a toner image. The printer further includes an endless belt stretched around a drive roller and a tension roller, and transfer rollers disposed to face the respective photosensitive drums with the endless belt therebetween. As a sheet is conveyed by the endless belt, the toner images of the respective colors are sequentially transferred onto the sheet in a superposed manner by the transfer rollers, so that a color toner image is formed on the sheet. The color toner image is fixed to the sheet by a fixing unit.
However, in an image forming apparatus having a belt, an abnormal sound may occur when the belt runs.